Eco‐Friendly, High‐Loading Luminescent Solar Concentrators with Concurrently Enhanced Optical Density and Quantum Yields While Without Sacrificing Edge‐Emission Efficiency

Abstract

A luminescent solar concentrator (LSC) consists of loaded luminophores and a waveguide that can concentrate direct and diffuse sunlight, which is a crucial ingredient for developing solar glasses. In general, the loading concentration in LSCs is strongly restricted (typically <1 wt.%) to mitigate concentration-induced quenching (CIQ), reabsorption losses, and aggregation-induced scattering (AIS). However, this will induce transmission losses in particular for thin-film LSCs. To address all aforementioned issues, large-Stoke-shift LSCs with different loadings are simply prepared based on thiolated gold nanoclusters (GSH-AuNCs) dispersed in the polyvinylpyrrolidone (PVP) matrix. In contrast to conventional luminophores with a severe CIQ effect, photoluminescence quantum yields (PL-QYs) can be significantly enhanced up to %25% (from 0.5 to 1%) even under high loading of %26 wt.%. Such PL-QY enhancement is attributed to the synergistic effects of the suppression of non-radiative relaxation and enhancement of radiative decay processes due to surface ligand-matrix coordination. In addition, our high-loading LSCs also exhibit excellent optical quality and film uniformity without introducing noticeable AIS effects. Thanks to those unique properties, eco-friendly LSCs with high optical density can still hold a high edge-emission efficiency of %70% due to minimal reabsorption and scattering losses, yielding an external quantum efficiency of %15% at the wavelength of 400 nm.

Electronically Coupled Gold Nanoclusters Render Deep-Red Emission with High Quantum Yields

“…Atomically precise, ligand-stabilized metal nanoclusters (NCs), such as gold, silver, and copper NCs, can be simply synthesized under mild conditions without involving toxic elements and hazardous solvents . Moreover, they possess several fascinating photophysical properties, such as tunable absorption/emission, large Stokes shifts, and intramolecular charge-transfer (ICT) excited states. , As a result, metal NCs have been explored for several optoelectronic applications, such as LSCs, photovoltaic devices, and solar water splitting. − However, their photoluminescence (PL) QY is still low (typically far less than 20%), in particular, for red/NIR AuNCs with the ICT states due to the energy-gap law (large nonradiative decay rates, k nr ) and small wave function overlap between the excited and ground states (small radiative decay rates, k r ). − So far, the exact PL mechanism for ligand-stabilized AuNCs is still elusive, which should involve both contribution from surface ligands and kernel metals, as well as their synergistic interaction. − …”

o-Carborane-based fluorophores as efficient luminescent systems both as solids and as water-dispersible nanoparticles

“…Noticeably, an outstanding  PL of 0.54 was obtained from films of NPs, which is comparable or even higher to quantum yields of previously reported LSC dyes. 15 In conclusion, this study demonstrates that water insoluble ocarborane based fluorophores can be dispersed in water by preparing NPs unprecedentedly in a controlled manner. We have proved that the fluorenyl derivative 2, with octyl groups, is an excellent AIEgens in solid state ( PL = 0.71) and films ( PL…”

“…Noticeably, an outstanding Φ PL of 0.54 was obtained from films of NPs, which is comparable or even higher to quantum yields of previously reported LSC dyes. 15…”

Earth abundant colloidal carbon quantum dots for luminescent solar concentrators

“…During the last forty years, luminescent solar concentrator (LSC) technology has attracted a lot of attention as a solar-light harvester, which can significantly reduce the cost of electricity by decreasing the active area of silicon solar cells used for generating the same amount of power, if the PCE of the LSCs is higher than 6%. [25][26][27][28][29] In addition, LSCs could be very suitable for application in building-integrated photovoltaic (BIPV) applications due to their transparent or semi-transparent nature, light weight, and lowlight intensity photovoltaic (PV) response. 30,31 An LSC typically consists of a plastic optical waveguide doped with highly emissive fluorophores (e.g.…”